by Staff Writers
Nuremberg, Germany (SPX) Jul 14, 2017
Physicists at Friedrich-Alexander-Universitat Erlangen-Nurnberg (FAU) and Friedrich Schiller University Jena (FSU) have accomplished a quantum leap in light research. They have managed to capture the behaviour of extremely short laser pulses during focusing by means of very high spatial and temporal resolution.
The results are of fundamental relevance to understanding the interactions between light and matter and will make it possible to control electron movements and chemical reactions to an extent that was previously not feasible.
These insights into fundamental physics will particularly profit further research into new radiation sources and in the field of light wave electronics. The researchers recently published their findings in the leading specialist journal 'Nature Physics'.*
Ultrashort light pulses with such a wide optical spectrum range that the beams appear white are in common use nowadays. Among other things they are used to examine the retina of the eye while in physics they are employed to control processes at the atomic level and analyse them in slow motion.
In almost all these applications, the white laser pulses need to be focused. As it is the specific form of the light wave that determines how electrons, for example, will move within it, it is essential to know what the focused laser beam actually looks like in detail.
In order to better understand why, think of a ship in stormy seas. The helmsman not only has to know how high and how long the waves are but also has to keep an eye on incoming waves in order to know when they will hit the ship in order to find a safe path up to the crest of the wave on one side and down on the other.
In the same way, it is important for researchers to know how and where the maximum of a light wave will strike electrons in an experiment or application in order to have a targeted influence on them.
The changes to and propagation of light waves in an electrical field take place on a time scale of a few hundred attoseconds - in other words, within one billionth of a billionth of a second. Until recently, it was not possible to measure the exact distribution of the wave troughs and peaks at the focus of a laser beam on this time scale.
The researchers in Erlangen and Jena have now achieved this by focusing laser pulses onto a nanometre-sharp metal tip, causing the tip to emit electrons. These electrons act as a kind of sensor that enables the researchers to interpret the exact form of the light wave.
Watching light travel
The results obtained in the joint project have added to our understanding of the effect, so that even when it comes to short light pulses - and to stay with the metaphor for the moment - no captain will be taken by surprise by unexpected waves in future.
'Tracing the phase of focused broadband laser pulses' has been published in the journal 'Nature Physics'
Copenhagen, Denmark (SPX) Jul 14, 2017
Quantum physics: Scientists at the Niels Bohr Institute by University of Copenhagen have been instrumental in developing a 'hands-on' answer to a challenge intricately linked to a very fundamental principle in physics: Heisenberg's Uncertainty Principle. The NBI-researchers used laser light to link caesium atoms and a vibrating membrane. The research, the first of its kind, points to sensors cap ... read more
University of Erlangen-Nuremberg
Understanding Time and Space
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement|